Device for basting applied to sewing machines of the zigzag type



L. BONO March 12, 1968 vDEVICE FOR BASTING APPLIED TO SEWING MACHINES OF THE ZIGZAG'TYPE Filed Oct. 5, 1965 FIG-.3

FIG 4 United States Patent ice 3,372,660 DEVICE FOR BASTING APPLIED T SEWING MACHINES OF THE ZIGZAG TYPE Luigi Bouo, Pavia, Italy, assignor to Necchi Societa per Azioni, Pavia, Italy Filed Oct. 5, 1965, Ser. No. 493,084 Claims priority, application Italy, June 3, 1965, 12,428/65, Patent 772,518 Claims. (Cl. 112-158) ABSTRACT OF THE DISCLOSURE An accessory device for selective mounting on a zigzag type sewing machine for adapting same to sew basting type stitches. The device requires that the machine needle be removed from the machine needle bar and remounted in a needle holder which forms part of the device, said needle holder being reciprocably mounted and traversing one of the two axes along which the needle bar reciprocates whereby said bar abuts against the holder while said bar is along only one of said axes but slides past the holder when the bar is along the other of said The present invention refers to a device for basting applied upon a sewing machine adapted to execute sewing stitches of the zig-Zag type.

In usual family-type machines, there may be executed sewing stitches having a limited length; in said machine each forwarding movement of the carrier members is accompanied by a vertical oscillation of the needle for the formation of a sewing stitch upon a fabric. As is well known, the basting stitches, in order to be easily unstitched, must have a longer length than the maximum which is obtainable with usual type of sewing machine. The object of the present invention is to create an accessory device sufliciently simple, which may be applied at will to a usual sewing machine and be adapted to alter the normal sequence between the carrier member impulses upon the fabric and the vertical oscillation of the needle, in a manner such that there is cyclically a vertical oscillation of the needle after a certain number of consecutive impulses of the carrier. In order to realize this object, the device of the present invention comprises a needle mounted on a needle-support which is free to carry out alternate, substantially vertical movements along a fixed guide by means of an intermittent coupling which is created between the fixed support of the needle and the lower end of the usual needle-bar, having the needle removed therefrom, when this last element is shifted, with a pre-determined frequency in a preselected of two lateral positions corresponding to the zig-zag sewing. Preferably said guide is housed upon a small cylinder attached rigidly to the pressure foot of the machine and said needle support is connected rigidly to a small piston slidable within said cylinder against the action of an elastic biasing means.

An example of an embodiment of the present invention will now be described with reference to the accompanying drawing in which:

FIGURES 1 and 2 show two frontal views of the device in which the needle-bar is shown in two opposite lateral positions;

FIGURE 3 is a lateral view of the same device as that shown in FIGURES 1 and 2; and,

FIGURE 4 isa detail sectional view, on an enlarged scale, of the device of FIGURES 1, 2, and 3.

With reference to the drawing, 6 indicates the lower end of the needle-bar of a usual sewing machine of the zig-Zag type. To the fabric presser bar 7 of said machine there is fixed by means of screws 8 a special presser foot 9 comprising a hollow cylinder 10 connected rigidly by 3,372,660 Patented Mar. 12, 1968 clamp 11 to said fabric presser bar. In correspondence to its lower end, the cylinder 10 is connected rigidly to the support 12 of the base 13 of the special presser foot. Within the cylinder 10, there is a coil spring 5 resting at one extremity thereof against the lower head of the cylinder and enclosed along an upper portion thereof in a hollow piston 14, which is upwardly closed and free to slide within the cylinder 10.

The upper extremity of the cylinder is closed by a plug 15 mountable on said upper end in usual manner. The cylinder 10 presents upon its lateral surface, an opening 4 which extends vertically along the entire length of the cylinder; in this opening there may slide an appendage 16 which rigidly connects the lower end of the piston 14 to a needle-support 17 which carries in .a usual manner a sewing needle 18. With reference to the exemplary embodiment above described, the needle-bar 6 of the machine is shown as having its needle removed therefrom, the needle having been transferred to the needle support 17 in the accessory device of this invention. The machine needle bar 6 which normally performs axial oscillations, is induced by usual means which are not herein described to move intermittently from a first extreme lateral position, in which there is no interference between the needle-bar and the needle-support 17 which is mounted upon the special fabric presser foot 9 (FIGURE 1) to the opposite lateral extreme position in which the lower free end of the needlebar, during its alternative descending stroke, presses upon the needle-support and forces it to follow the needle bar along its stroke (FIGURE 2). When the needle-bar stroke begins in an upwardly direction, the needle is forced to reassume the rest position, out of the fabric, by means of the spring 5 which acts upon the piston 14. The actuation of these transverse intermittent movements of the needle-bar may be obtained by means of an appropriate cam connected by usual kinematic means to the needlebar support; said cam being configured in such a manner as to keep the needle-bar 6 in the position of non-interference relative to the needle-support 17 for a consecutive plural number of oscillations of this needle-bar, said cam then shifting said bar, during a period corresponding to one of its axial oscillations, in the opposite lateral position in which comes about the interference between the needle-support and said needle-bar. There are obtained in this manner, long sewing stitches upon the fabric since each vertical stroke of the needle is followed by a more or less long sequence of advancing impulses on the fabric.

It is evident that other embodiments may be employed to obtain an analogous effect to that above described; there could for example, in a sewing machine for effecting straight stitching, be provided a means to transversely shift the special presser foot so as to intermittently position the needle in alignment with the trajectory, in this case laterally fixed in space, of the needle-bar having the usual axial alternative movement.

It is to be understood, therefore, that the invention is not to be limited to the details therein disclosed but that it is intended to cover all possible obvious modifications which can be interpreted as falling within the scope of the following claims.

What is claimed is:

1. A removably attachable accessory device for sewing basting stitches with a sewing machine of the type which is adapted to sew in a zig-zag pattern by means of a needle bar which is axially oscillatable at each of opposed lateral positions, said device comprising a special presser foot means rigidly and removably attachable to a machine fabric presser bar, a needle support carried by said presser foot means, said needle support being reciprocable relative to said presser foot means and including means to rigidly mount a needle, abutment means on said needle support having a transverse extent such that it is adapted to transverse one of the axes along which the needle bar reciprocates during normal zig-zag sewing and thereby be abutted by the machine needle bar during its downward stroke along said one axis, the transverse extent of said abutment means being limited to terminate at a point between said axes whereby the needle bar may reciprocate along the other of said axes without contacting said support, means to move said needle support in an upward direction.

2. The accessory device of claim 1, wherein said last mentioned means comprises an elastic means biasing said needle support in an upward direction, said needle support being downwardly movable against the bias of said elastic means.

3. The accessory device of claim 1, wherein said special presser foot means comprises a hollow cylinder, means to rigidly and removably mount said cylinder on the machine presser bar with its cylindrical axis substantially vertical, a piston means slidable within said cylinder, spring means biasing said piston means towards the top of said cylinder, said needle support being connected to said piston means for integral axial movement therewith.

4. In a zig-zag type sewing machine comprising a fabric presser bar and a reciprocable needle bar adapted to reciprocate at opposed lateral positions, said needle bar having a lower end and including a means to removably mount a sewing needle at said lower end thereof, the improvement comprising an accessory device for sewing basting stitches, said device comprising a presser foot means rigidly attached to said presser bar, said presser foot means comprising a reciprocal needle support for mounting a sewing needle generally parallel to vertical axis of said needle bar, one extreme lateral axial trajectory of said needle bar intersecting a lateral surface of said needle support and the opposite lateral trajectory being laterally spaced from said needle support, means urging said needle support upwardly, means to laterally shift said needle bar from one to the other of said lateral positions in accordance with a particular sequence of axial reciprocations thereof.

5. An accessory device for sewing basting stitches, said device comprising a needle support for mounting a sewing needle, a housing, said support being reciprocably mounted on said housing, means to mount said housing on a conventional sewing machine with the reciprocatory axis of said needle support running in the same general direction as the reciprocatory axis of the machine needle bar, means on said support for engaging the machine needle bar and for being driven by said bar in one axial direction, means urging said support in the opposite axial direction, said housing comprising a hollow cylinder, a piston axially slidable within said cylinder, said piston being connected to said needle support for integral movement therewith, said needle support comprising an upper abutment surface adapted to be abutted by the lower end of a needle free needle bar, spring means within said cylinder urging said piston upwardly.

References Cited UNITED STATES PATENTS 1,187,074 6/1916 Loeb 112158 RICHARD J. SCANLAN, JR., Primary Examiner. 

